Resmed S9 clock problem

My travel Resmed S9 system has been around the world with me this summer but now the clock is "stuck" a day and a few hours ahead. I cannot get the clock to set "back" - I get an error message that data already exists.

Anyone know how to fix this? I want to swap my machines over but this data error is going to screw up my tracking..

TIA

You might have to clear your data.
I had the same situation, but was going to use my backup machine so I could skip a day.
Then I decided it didn't really matter enough to me, so I left it alone.

ResMed devices really "hate" to be set back, probably because it would allow manipulation of compliance data. As Cf says, one way is to reset (erase) the data (see the clinical manual). Another way that might work (I haven't tried it) - try setting it back a few hours over a few days, just don't set it back to a previous calendar date or into a time that contains data. I've learned the best thing to do when traveling is just to leave the machine set to the "home" time.

Clinical Manual wrote:If you set a new date or time
that occurs in the past then an
‘Invalid date/time, data exists
for this period’ message is
displayed.
Before this change can be
made, erase the compliance
data – available under the
Configuration menu.

Will it not allow a back date after a couple/three days have gone by without your using the machine at all?
If it won't allow the back date after 2 or 3 days of no use at all the only thing you can do is a total reset of the data and that means erasure of all past data...start fresh with the machine and SD card too.
I had to do it once because some how or other I accidentally set the machine a day ahead...though I don't remember doing it so maybe it was the aliens. I just bit the bullet and did the total reset thing. I had all the old data in the software anyway so really not a big deal to not have it on the machine or SD card.

Reset it and it seems fine now. I have backed up card too

If you don't want to erase your data, you can go back, but only to where there is no data. For instance:

Get up at 8 AM, turn machine off.
Don't use machine until 10 PM.
You can then set the time back to 8:01 AM.
Repeat the next day until you can get back to the correct time.

Inconvenient, and leaves you with screwy data for a few days, but seems work. It would be a real pain if you're a year ahead.

Lost one day of data and otherwise seems OK.